Fiber, although integral to a healthy diet, can have negative side effects when consumed in excess. These side effects include loose stools, abdominal discomfort and gas. Excess fiber can also make it difficult for the body to absorb certain nutrients, such as zinc, iron, calcium and magnesium, according to WebMD.
Fiber supplements typically come in two general types: soluble and insoluble. Soluble fibers help lower cholesterol, and research shows they may help manage diabetes. Insoluble fiber assists with regularity, as it accelerates the movement of food through the body. Most experts recommend consuming fiber naturally found in food, rather than taking a fiber supplement.